import java.util.*;
public class text {




      public class ListNode {
       int val;
        ListNode next = null;
        public ListNode(int val) {
          this.val = val;
        }
      }


    public class Solution {
        /**
         * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
         *
         * @param head ListNode类
         * @return ListNode类
         */
        public ListNode ReverseList(ListNode head) {
            // write code here
            ListNode prev = null;
            ListNode cur = head;

            while (cur != null) {
                ListNode next = cur.next;
                cur.next = prev;
                prev = cur;
                cur = next;
            }

            return prev;
        }
    }
}
